154
AWUS01 KWNH 271802
FFGMPD
VAZ000-TNZ000-KYZ000-INZ000-ILZ000-MOZ000-280000-
MESOSCALE PRECIPITATION DISCUSSION 0540
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
200 PM EDT SAT JUN 27 2026
AREAS AFFECTED...PORTIONS OF THE OH VALLEY
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY
VALID 271800Z - 280000Z
SUMMARY...LOCALLY REPEATING ROUNDS OF EXTREMELY HEAVY SHOWERS AND
THUNDERSTORMS WILL CONTINUE OVER THE NEXT SEVERAL HOURS.
SIGNIFICANT AND LIFE-THREATENING FLASH FLOODING WILL REMAIN A
THREAT INTO THE EVENING HOURS.
DISCUSSION...THE EARLY AFTERNOON GOES-E VISIBLE SATELLITE IMAGERY
ALONG WITH THE LATEST RADAR SHOWS BROKEN AREAS OF VERY HEAVY
SHOWERS AND THUNDERSTORMS STILL IMPACTING PORTIONS OF CENTRAL KY,
WITH RECENT STRONG DEVELOPMENT SEEN OVER PARTS OF SOUTH-CENTRAL
IL. ADDITIONALLY, A VERY WELL-DEFINED MCV IS NOTED OVER SOUTHEAST
MO WHICH IS ADVANCING STEADILY OFF TO THE EAST. THIS ENERGY HAS
BEEN A MAJOR FACILITATOR OF THE RECENT DEVELOPMENT OVER
SOUTH-CENTRAL IL AND IS ALSO DRIVING SOME POCKETS CONVECTION
ACROSS FAR SOUTHERN IL AND FAR WESTERN KY.
REGIONALLY, THE AIRMASS REMAINS VERY MOIST WITH HIGH PWS REACHING
2.0 TO 2.25 INCHES, AND THIS IS SUPPORTED BY THE LATEST OSPO ALPW
DATA WHICH SHOWS HIGH MOISTURE CONCENTRATIONS WELL UP INTO THE
300/500 MB LAYER. MEANWHILE, A SUBSTANTIAL POOL OF INSTABILITY IS
BECOMING INCREASINGLY FOCUSED UP ACROSS SOUTHERN IL DOWN THROUGH
WESTERN KY. SOLAR INSOLATION HAS DRIVEN MLCAPE VALUES OF 1500 TO
2500 J/KG ACROSS THESE AREAS, AND THIS IS BUMPING UP AGAINST AN
OUTFLOW BOUNDARY AND DOWNSTREAM COLD POOL ACROSS PORTIONS OF
SOUTHERN IN AND CENTRAL KY.
THE CONCERN MOVING FORWARD THIS AFTERNOON AND INTO THE EVENING
HOURS WILL BE THE UPSTREAM MCV OVER SOUTHEAST MO WHICH WILL MOVE
GRADUALLY ACROSS SOUTHERN IL AND INTO WESTERN KY. THIS SHOULD
INTERACT WITH THE STRONG THERMODYNAMICS DOWNSTREAM TO DRIVE AN
UPTICK IN CONVECTION AND INCREASINGLY HIGH RAINFALL RATES.
HOWEVER, THE INCREASING WARM AIR/THETA-E ADVECTION AROUND THE
EASTERN FLANK OF THE MCV WILL LIKELY INTERACT WITH THE DOWNSTREAM
AFOREMENTIONED OUTFLOW BOUNDARY/COLD POOL FOR AN ISENTROPIC
COMPONENT TO THE CONVECTIVE THREAT. REGENERATING AREAS OF
EXTREMELY HEAVY SHOWERS AND THUNDERSTORMS MAY OCCUR IN TIME ACROSS
AREAS OF SOUTHWEST IN ON DOWN INTO CENTRAL KY AS THIS PROCESS
PLAYS OUT BY LATER THIS AFTERNOON.
A 30 TO 40+ KT SOUTHWEST LOW-LEVEL JET IS ALREADY IN PLACE, AND
THIS FOCUSING OF MOISTURE/INSTABILITY TRANSPORT UP INTO THE LOWER
OH VALLEY COUPLED WITH THE MESOSCALE BOUNDARIES AND AFOREMENTIONED
VORT ENERGY WILL SUPPORT CONVECTION WITH EXTREME RAINFALL RATES. A
HIGHLY CONDUCIVE ENVIRONMENT FOR BACKBUILDING AND TRAINING
CONVECTION WILL EXIST WITH THE PERSISTENCE OF WEAK AND NEARLY
OPPOSING CORFIDI VECTORS.
RAINFALL RATES ARE LIKELY TO REACH 2 TO 3+ INCHES/HOUR, AND THE
LATEST MULTI-MODEL HIRES CAMS SUPPORT AS MUCH AS AN ADDITIONAL 3
TO 5+ INCHES OF RAIN THROUGH EARLY THIS EVENING. ALREADY A NUMBER
OF FLASH FLOODING REPORTS, INCLUDING A COUPLE OF CATASTROPHIC FFW
ISSUANCES (IN CENTRAL KY) HAVE MATERIALIZED TODAY. THE ADDITIONAL
RAINFALL OVER THE NEXT SEVERAL HOURS WILL MAINTAIN A REGIONAL
THREAT FOR SIGNIFICANT AND LIFE-THREATENING FLASH FLOODING.
ORRISON
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...ILN...ILX...IND...JKL...LMK...LSX...MEG...MRX...
OHX...PAH...
ATTN...RFC...KRF...MSR...ORN...TIR...NWC...
LAT...LON 39268901 39248707 38848546 38218429 37268335
36438320 35868405 35858596 36248809 36998995
37879071 38769047
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